“Slo-Mo” TAC Anti Speed TV Ad

Many people were skeptical that driving 5 km/h slower could make a difference to speed on impact.

With the help of crash expert Dr Ian Johnston, and an airfield, it is shown conclusively that a 5km/h difference when braking makes a 27km/h difference on impact.
Launched: 2002.
Victorian Road Toll that year: 397.

“Copyright in the material on this website is owned by the TAC and may only be used for non-commercial personal or educational purposes. You may not modify, transmit or revise the contents of this website without the prior written permission of the TAC.”

Let’s make the discussion educational…I have been reading a lot about crashes lately and this video thanks to Kevin 😉  may put things into perspective how slowing down a little can make a difference. 


  1. Doug Mullett says:

    I live in Victoria. A lot of the material presented in TAC and other ads relating to road safety have been “doctored” to create an impression different from reality.
    In this case, if the cars brake at the same rate (a function of tyre grip, brake pressure and ABS operation), therefore with the same and constant deceleration (-a) and cover the same distance (x), then the difference between the squares of the final and initial velocities must be the same. They are not.
    I would like to see the times and distances given, and also multiple trials with drivers swapped between the cars, before I would give any credence to the figures.

  2. Doug Mullett says:

    However, even given the above, I drove on a simulator for learners (1991) in country Victoria. The scenario presented was of a main street. I drove at 60. A corner came up and we entered a street with cars parked on both sides. I automatically slowed so I could see signs of activity (brake lights, exhaust movement or smoke, balls or toys rolling or moving into view). I was remonstrated with and told I had to drive at the speed limit. I replied that the reason why I hadn’t hit other cars and people was I learned to adjust my speed to conditions. I was told that’s not the way it’s done.
    If you examine the change in legislation re driving in Victoria, it supports blind adherence to inflexible laws but does not support driver responsibility. An example is the use of speed cameras to detect and fine driving as little as 3 km/hr over the speed limit (yet design rules for earlier cars permits +/- 10% for speedometers). The offence is detected but not notified until weeks later. But poor and dangerous driving often goes undetected (driving in emergency lanes, tailgating, erratic lane changing, speeding between cameras) as there are few police on the road.
    Sorry, but I’m passionate about road safety and speed cameras (in particular) have brought into disrepute a system which led the world with seat-belt legislation and random breath tests and so brought about dramatic decreases in the road toll. MUARCs current position seems to be lowering speed limits will solve all problems (“Speed kills” campaign) yet our safest roads have the highest speed limits.

  3. advgrrls says:

    great points…I wonder though the roads with high speed limits have density regarding populations and cars?

  4. Doug Mullett says:

    Our safest roads are freeways (very similar to US Interstates) with 110 km/hr. Freeways with 100 km/hr are not as safe. The density is not a factor in the safety stakes, rather the road engineering and lack of grade crossings. In fact, accidents which do occur on them often happen at times of low traffic density, usually because of speed differentials.

  5. Doug Mullett says:

    An interesting book, old but still relevant, written by an engineer, is “Prevent or Punish”. One interesting fact pointed out is that because most humans are “right-eyed” (i.e. have a dominant right eye), simply switching to RHD throughout the world would lower fatalities by up to 15% as more correct overtaking decisions would be made.

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